The present invention relates to a fuel injector for an internal-combustion engine, and the corresponding method of manufacture.
Injectors are known in which the bobbin of the coil carries a pair of hollow appendages, inserted in which are the two plugs, which are rendered fixed with the coil, for example by means of a block or disk made of non-magnetic material. This block is relatively costly to manufacture, both with regard to the mechanical machining and with regard to its assembly.
In a known injector, in which the two plugs are parallel to the axis of the core, it has been proposed to englobe in a block made of non-magnetic plastic material both the core and a portion of the plugs, which hence constitute inserts in the injector for moulding of the block itself. In such an injector, the bobbin has an outer diameter such as to define, in the annular slot of the core, a passage for the plastic material, which at the moment of injection in the mould totally coats the coil. This injector presents the drawback of preventing dissipation of the heat produced by the coil, following upon excitation of the electromagnet. In fact, the coil is completely coated by the plastic material, which reduces substantially the heat-exchange capacity thereof with the environment, in particular its capacity for transmitting the heat produced to the diesel fuel, which flows through the magnetic core to be subsequently disposed of.